Micromechanical sensors are used in various technical applications. Among others, capacitive acceleration sensors are used which have a detection direction perpendicular to the wafer plane (z direction) and which are designed in the form of a rocker. This sensor principle is based on a spring-mass system in which the motion of a suspended seismic mass which is elastically deflectable with respect to a substrate is capacitively detected. The mass is suspended with the aid of a torsion spring in such a way that mass structures of different sizes result on either side of the torsion spring. The action of an acceleration causes the mass structure to rotate about a rotational axis which is predefined by the torsion spring.
However, such a spring-mass system also responds to accelerations in the plane which is orthogonal to the preferred detection direction, resulting in undesirable vibrations of the sensor mass in this plane. In the case of resonance, these vibrations may result in striking of the rocker, and thus, in interference signals in the range of the measuring range. Two in-plane modes have proven to have a particularly adverse effect on the useful signal: namely, a rotational vibration of the sensor mass about a rotational axis parallel to the detection direction, and a translational vibration in the longitudinal direction of the mass.